Enhanced 2?m emission behavior and energy transfer in Ho3+/Yb3+co-doped bismuth-tellurite fiber-core glasses by CeO2

Ho3+/Yb3+ co-doped and Ho3+/Yb3+/Ce3+ tri-doped 85TeO2-5Bi2O3-10ZnO glasses were synthesized by the melt-quenching method. The structural and spectral properties were investigated comprehensively according to Raman, absorption, and fluorescence spectra. By evaluating the energy transfer process, the 2 mu m emission behavior has been enhanced effectively with the introduction of a glass network modifier (CeO2), which can be ascribed to the population of Ho3+: 5I7 accelerated by cross-relaxation (CR) between Ho3+ and Ce3+. A large emission cross-section (1.11 x 10-20 cm2) and gain coefficient (2.12 cm-1) have been obtained of Ho3+ at around 2 mu m band in TBZHYC2 glass, where a significant advancement has been achieved compared with the glass fiber core without CeO2. Moreover, the energy transfer mechanisms between Ho3+/Yb3+ and Ho3+/Ce3+ were quantitatively analyzed based on a spectral overlap method. As mentioned above, Ho3+/Yb3+/Ce3+ tri -doped bismuth-tellurite glasses are potentially competitive and applicable in the field of 2 mu m band infrared fiber lasers as a kind of novel laser glass.

Automated summary

Ho3+/Yb3+ co-doped and Ho3+/Yb3+/Ce3+ tri-doped 85TeO2-5Bi2O3-10ZnO glasses were synthesized and their structural and spectral properties were comprehensively investigated. By introducing CeO2 as a glass network modifier, the 2 μm emission behavior was effectively enhanced through the cross-relaxation between Ho3+ and Ce3+. A large emission cross-section and gain coefficient were achieved in the TBZHYC2 glass, indicating its potential as a novel laser glass for 2 μm band infrared fiber lasers. The energy transfer mechanisms between Ho3+/Yb3+ and Ho3+/Ce3+ were also analyzed quantitatively.